core java volume fundamentals

-code unit S u+d835 and u+dd6b. (see http://en.wikipedia.org/wiki/UTF-16 for a description of the encoding algorithm.) in Java, the char type describes a code unit in the UTF-16 encoding.Our strong recommendation isn't to use the char type in your programs unless you are actually manipulating UTF-16 cod E units. You is almost always better off treating strings as abstract data types.3.3.4. The Boolean Type The Boolean type has two values, false and Tr

Tag: Util indicates date () Date class specifies date standard int ringIn the Java core Technology volume, the first date class appears in a very high frequency, so we have a small integration of the date classThe date class has twoThe date class represents a specific time classThis constructor assigns a Date object and initializes it to represent the specified n

Lambda An expressionform: parameter, arrow (-), expressionParameter type to write, if you can deduce it can not writeOnly one argument can omit parenthesesNo arguments to write empty brackets ()* If the branch returns a value, then all branches will return a value, otherwise it is illegalfunction interface: interface with only one abstract method (can be marked with @functionalinterface annotations)For example, you can do this in Javax.swing.Timer.　　　　　　Timer T = new timer (+, event-{...});The s

For this code, a lot of netizens are full of questions, first there are many, not careful, did not write the pair class, to compile.Certainly compiled, the pair class is on the first two pages of the other code.And here, the features of generics are written. By several constructors, and the change of parameters, the generic type is explained.Package pair1;public class pairPrivate T first;Private T second;Public Pair () {first = null;second = null;}Public Pair (t first, t second) {This.first = Fi

schematic, the inside of the compiler is certainly not outer An implicit reference to an external class is set in the constructor. The compiler modifies all constructors for the inner class, adding a parameter that references the external class. Even if you do not define a constructor for an inner class, the compiler generates a default constructor for the inner class. such as:Publictimeprinter (talkingclock clock) {outer = clock;}When an inner class object is created in the Start method, th

class does not have a way to modify the strings, if you really want to change them The following expressions are legal The = = operator detects whether two strings are placed in the same position In fact, only string constants are shared, and the results of operations such as + or substring are not shared Issupplementarycodepoint (int codepoint) is a Boolean method of the character class that determines whether the specified character (Unicode code point) i

FileOutputStream can provide input and output streams attached to a disk file. The parameter is a file name or full pathname.Use System.getproperty ("User.dir") to get the current pathSystem. out. println (System.getproperty ("user.dir")); -D:\WorkSpace\Eclipse\IOTestThe full path we need to get the operating system operator, such as under Windows:System. out. println (File.separator); -/ You can also use the double backslash notation: c:\\windows\\123.txtA basic read-file program:ImportJav

34 Return 35 instanceof 36 Static 37 Final 38 Super 39 This 40 Native 41 Strictfp 42 Synchronized 43 Volatile

Basic data typesJava is the language of a strong data classThere are 8 basic data types, including:Integer 4 types Int (4 bytes) short (2 bytes) long (8 bytes) byte (1 bytes)The range and machine-independent lengths of integers in Java are certain, and do not cause integer overflow across platformsFloat type two double floatThe length of the double is twice times the length of the float, the double value but the part is used double, at the time of pre

box containing a message and an OK button, which will be in the center of its parent component.API javax.swing. Timer 1.2Timer (int interval, ActionListener Listener)Constructs a timer that advertises listener once every interval millisecond.void Start ()Start the timer. Once the boot is successful, the timer invokes the listener's actionperformed.API void Stop ()Stop the timer, and once the stop is successful, the timer will not be actionperformed to call the listener.Java. Awt. Toolkit 1.0Sta

1. Static constants:Static variables are used relatively little, but static constants are used more, for example, a static constant is defined in the Math class:public static Final PI = 3.141592653;In the program, this constant can be obtained in the form of Math.PI.If the keyword static is omitted, Pi becomes an instance field of the math class and needs to be accessed through an object of the math class, and each math object has its own copy of Pi."Java